B12 deficiency with neurological manifestations in the absence of anaemia

Vitamin B12 deficiency is often diagnosed with hematological manifestations of megaloblastic macrocytic anemia, which is usually the initial presentation. Neurological symptoms are often considered to be late manifestations and usually occur after the onset of anemia. Sub acute combined cord degeneration, which is a rare cause of myelopathy is however the commonest neurological manifestation of vitamin B12 deficiency.

We present a case of a 66 year old Sinhalese Sri Lankan female, who is a strict vegetarian, presenting with one month's history suggestive of Sub-acute combined cord degeneration in the absence of haematological manifestations of anaemia. Her Serum B12 levels were significantly low, after which she was treated with hydroxycobalamine supplementation, showing marked clinical improvement of symptoms, with normalization of serum B12 levels. Hence, the diagnosis of vitamin B12 deficiency was confirmed retrospectively.

Vitamin B12 deficiency could rarely present with neurological manifestations in the absence of anaemia. Therefore a high index of suspicion is necessary for the early diagnosis and prompt treatment in order to reverse neurological manifestations, as the response to treatment is inversely proportionate to the severity and duration of the disease.